Nanotechnology is a term used for miniaturization in all areas of science. A nanometer is a billionth of a meter, and science--chemistry, engineering--is now pressing down to this level of manipulation. The future is there: it’s where we’ll have the most power to manipulate the natural order, and that’s why it’s so exciting, but it’s also why it raises such big questions.

We will be able to miniaturize everything. For example, those tags you have on groceries in the store, which are radio frequency identifiers, are going to get smaller and almost free—so small you can’t see them. This is great for inventory control in Wal-Mart—every product you ever buy could be tracked forever. But issues of privacy and confidentiality are raised in profound ways.

Could someone put the small thing that’s normally on a CD in Wal-Mart into my sandwich? If I eat it, can I be tracked?

Indeed so, unless you have a mechanism that requires these things to be deactivated at point of sale or in some other way. And of course you could still get criminals using them.

Most of the sunscreen now sold in the U.S. contains nano-sized particles. I have no reason to believe they are not safe, but there are huge debates about how we deal with particles that are so small they can cross the blood-brain barrier. We have very little evidence of their long-term impact and the whole toxicology issue is enormously complicated.

In terms of tracking people, what problematic scenarios can you envision?

Well, you don’t have to be a sci-fi writer or conspiracy theorist to see this as the end of privacy. If you have a government or commercial industries who want to know where everybody is, a surveillance society becomes much more practicable. Already you can put chips in your dog to find it if it strays.

At the other end of the scale, there’s talk about using a nano-device to create clean water.

You’d be able to drop some little particles in dirty water, and…?

--and it would just clean it all up, little machines that would replicate and eat up all the impurities. It sounds wonderful. On the other hand, you say what is the context for this? Maybe someone comes along and patents it and says, “You can’t use this unless you pay.”

This all feeds into the need for a policy discussion based on a notion of human values.

What health applications of nanotechnology can you envision?

Well, the National Cancer Institute on its website says that by 2015, cancer will be cured or be controllable as a chronic condition using nano-delivery devices as a way of getting drugs into cells.

I think it’s a somewhat irresponsible claim, because I’m sure it won’t happen by 2015. But some of the hopes for these technologies are incredible, and we have to enthuse and support the technology, even while, at the same time, having a conversation about its responsible use.

Some people think we should permanently incorporate tiny machines into our bodies to fix things.

There are people called transhumanists. Some of them are very engaging people, sort of sci-fi cultists, but now becoming part of the mainstream discussion. They’re scaring both people who like being human and people in the business community. What they want to do is use machines to turn us into cyborgs, half-human, half-machine things.

My impression was that if you were 80 years old and your arm joint had worn out, a machine would be put in to help with that, but you’d still have a human brain.

I have no problem with that. I have a sore knee right now! You don’t become a cyborg by having a hip replaced. What the transhumanists want to do is use nano-devices to live a life that ceases to be human.

In what way would the transhumanist scenario be non-human?

For example, they want to take people who have not had a bang on the head and put chips in their brains, what they call neuroprostheses. You can wire up your neurons with a computer.